The present invention relates to hermetic compressor assemblies, and in particular, to so-called xe2x80x9chigh sidexe2x80x9d rotary compressors in which the interior of the compressor housing, including the motor chamber, is at discharge pressure.
While it is known to provide a compressor mechanism rigidly mounted within a cylindrical housing, for example, as disclosed in U.S. Pat. No. 4,639,198, assigned to the assignee of the present invention, and expressly incorporated herein by reference, such an arrangement results in an undesirable transfer of vibrational noise generated by the compressor mechanism to an appliance in which the compressor mechanism is mounted. Additionally, sound waves associated with discharge pressure pulses are readily transmitted by discharge pressure gases, the molecules of which are densely packed. These sound waves impinge upon the housing itself, generating noise which is objectionable in the space in which the compressor itself is located. Compressors heretofore, specifically high side compressors, typically discharge the noise carrying gases, relatively unattenuated, through the housing to a discharge tube attached to the housing. Generally, an external noise attenuation device, such as a muffler or the like, is attached to the discharge tube, external to the housing, to assist with decreasing fluid borne noise. The addition of a muffler or other like externally mounted attenuation device adds significant cost and an undesirable increase in required space for the compressor unit.
Therefore, it is desirable to suppress operational vibration of the compressor mechanism and to muffle fluid borne noise immediately after the compression cycle and before the gases reach the interior surface of the housing, without adding significant cost to the compressor.
The present invention overcomes the disadvantages associated with prior hermetic rotary compressors in that it provides a compressor including a housing and a compressor subassembly resiliently supported within the housing. The compressor subassembly includes a motor drivingly coupled to a compressor mechanism by means of a shaft and a motor enclosure connected to the compressor mechanism encases the motor. A pair of grommets are disposed between the housing and the compressor subassembly to resiliently suspend the compressor subassembly within the housing.
In one form of the present invention, the rotary compressor, which draws a suction gas and discharges a compressed discharge gas, includes a housing and a compressor subassembly disposed in the housing. The compressor subassembly includes a motor drivingly coupled to a compressor mechanism by means of a shaft and a motor enclosure connected to the compressor mechanism encases the motor. A quantity of oil is disposed in a lower portion of the housing wherein at least a portion of the compressed discharge gas from the compressor subassembly is directed through the quantity of oil to form a sound damping foam.
In a preferred form of the invention, a first discharge chamber is defined by a main bearing, attached to the motor enclosure, and an inner surface of the motor enclosure. A second discharge chamber is defined by an inner surface of the housing and an outer surface of the compressor subassembly. The first and second discharge chambers are in fluid communication through an aperture provided in the motor enclosure. The first and second discharge chambers constitute a pair of mufflers which consecutively receive the discharge gas.
The present invention also includes a method to assemble a rotary compressor assembly which include steps, one step being, a method of assembling a rotary compressor comprising the steps of: providing a motor enclosure attached to a stator and a rotor attached to a shaft, the shaft supported by a main bearing. Another step includes inserting a mounting tool into a hole within the motor enclosure to engage the shaft and align the stator and rotor such that a radial air gap is substantially uniform between the stator and rotor. Yet another step includes joining the main bearing to the motor enclosure, and thereafter, removing the mounting tool from the hole in the motor enclosure. The remaining steps include fastening a compressor mechanism to the main bearing which engages with and is driven by the first end of the motor shaft to form a compressor subassembly and mounting opposite axial ends of the compressor subassembly into respective resilient mounts within an interior of a housing and hermetically sealing the housing.